使用messagebox java停止法规

I need to find a way to stop a while statement when a messagebox is closed in java. I am modifying a chat program, the server has no gui and listens with a while(true) statement. I am trying to find a way to close the server with out going into task manager and killing java.exe. I have little experience with java so some source code would be nice. Thanks for the help!I need to find a way to stop a while statement